Combined air vent valve and pressure relief plug



March 2, 1954 w. s. Kr-:NDRICK COMBINED AIR VENT VALVE AND PRESSURE RELIEF PLUG Filed Sept. 9, 1949 INVENTOR WILLIAM S, KENDRICK BY HIS ATTORNEYS vzmard Patented Mar. 2, 1954 UNIT-eo PATENT oli-Fica CQMBINED-A-IRVENT VALVE'ANDTPRES'SURE REEIEF PLUG Willian S. Kendrick. Willow Gfx-avala., assigner tu Proctor Electric Qompuxy, Philadelphia, Pa., corporation ofl'cxiinsvivanter Implicationl September 9, 1949; Serial No. 114,810

a Claimn- (01.. lai-467) This invention. relates to pressure cookers.: and

more particularly to anv improvement in -cleviceadapted for air vending and excess-presenterelease as disclosed in acopendingspplication .of C'. R.. Turnen Serial No... 674,70?, filed June 6, 1946 nowl U. S. Patent No. 2,6l9;982, issued De:- cember 2l 1952. t

The device disclosedinsaid patent `comprises a. resilient disc seated in an opening ina pressure cooker and a relatively movable member disposed in an orifice in the resilient discN An; important feature of that device is the ability of the movable member to be ejected throughl the oriilce Yoi.-; the retaining disc in the event that pressure ineX-f cess of the normal operatingpvalue is-attained within the cooker. Ilowever,. in performing this function, a problem is encountered. On ejection, the movable member infrequently lost.- and slib sequenty operation. oi the; pressure cooker. isfpre.- vented until this member is replaced.. Further. forcible ejection of the movable memberpresnts a source of hazard to the user.-

It is therefore'the principal objectot thisffinfvention to provide a pressure cooker `valve* of the type having a member movabletoelect-excess pressure venting, Withfmeans for preventing ejecf tionof the movable. mem-ber during. the eilzcess pressure venting peri-od. Other be evident from the descriptiony that follows.

For a complete understanding, of thisinventgim. reference should be had to theeccompan-ying drawing in which:

Fig. l is a view, partly in elevatiomandepartly in section, of the upper portion ci apressure cocker embodying the invention; i

Fig. 2 is an enlarged sectional viewshowingthe device provided by thisinvention inits: inoperative condition;

Fig. 3 is similar toFi-g', 2 with the movnblemember in the position that it normauy asswneswh'sn cooking pressure exists in the vessel;

Fig. 4 isk a similar view showing the devicein the excess pressure ventingxcond-ition;

Fig. 5 is a bottom View of the device;

Figs. 6 and 'l are large sectional views of. other embodiments of thenvention; and

Fig. 8 is aV bottom view of the device Shoa/'nin A 2 tion of QR; Turner, Serial No. 672,363, filed May 2.1, 1946-, now U. S. Patent No.2,5'70,993, issued October 9, 12951;. Disposed at. the central portion of the lid 2 is-a pressure control and indicating device 5 which. is adapted to maintain the correct operating pressure in the cooker and to give an audible indication ofcontinued application of excess heat to the cooker. The: pressure control and indicator" device is of: the form disclosed in the rstsmentioned Patent No. 2.5619382. Since'vthe present invention is not concerned .with the gen.- eral .construction of the pressure cooker orwith the pressure control and indicator device,V there ispo need. to: illustrate or describe-these structures. in detail.

In accordance with! the present. invention,`v there isprovided on the pressure cookerl a device 6 which is preferablyl mounted on the lid Z adjacent to venting-and indicating device 5; The'device -Bi includes a.. resilient seating and retaining member .l which is generally of annular form and whichA has; the cross: sectional shape shown in Fig. 2. This member may be formed of synthetic rubber orotherr suitable material. It is formed so as to provide peripheral retaining portions 8 and '9 between which is an annular recess l0. The lid 2 has a suitable opening ll within which the rememberv T may be positioned, the annular edge portion. of .the lid about said openingvseat ing in. recess l0, while portions 8 and 9 engage the upperl and. lower surfaces of said edge portion;

The resilient member 1' has an internal inwardly extending annular projection |22 having substandat upper and lower surfaces in whichthe-re tir-provided. an opening or orice i3. Amember i4; which' may be formed of metal or other-"relatively rigid material, is loosely supported bythe resilient member 1,. as: shown. The rigid member Mais providedl with a cap or stop l5 having a top.` wand a shoulder l1 to prevent said rigid; member from becoming disengaged from the resilient 'memberl when pressure does not exist. in the pressurc'cocker.. Below said cap is a cylln dricali portion le of 'suchdiameter as to provide a clearing space with the orifice I3 in said resilient member: Adjacent this cylindrical portion is an portion [shaving-a substantially conical shaped. upper portion for seating against the lower suriace of' the annular projection l2'.` The slope on the conical portion further cooperates the resilient member l for it acts to cam the inwardly extending annular projection l! upward so -thatpressures in the vessel in excess ofv the operating value. act to forcethe enlarged portion l of the member through 'the orifice vide sufficient clearance for unrestrained passage of steam through the orice.

The functions ef the device s mayV be bestl understood by considering the operation ofthe pressure cooker. Let us assume that the cooker has just been placed in operation and that heat4 is being applied thereto at a relatively high rate to bring the cooker rapidly to the desiredfoperat-y ing condition. Member I4 is in its normal position as shown in Fig. 2. As soon as the water Iinside the vessel l commences to boil, the generated steam forces the air out of the vessel through the venting device S. The spaces or clearances about the member i4 permit the air -f to escape. In a very short time after the attainment of boiling temperature, steam is generated with such volume as to cause suicient pressure within the vessel to raise the member Id, at which time the conical portion of the enlarged section I9 engages the lower edge of the annular projection I2 and effects therewith complete sealing of the venting opening, as shown in Fig, 3. This action of the device 6 permits building up of pressure within the vessel to the desired operating value, which is thereinafter controlled by the device 5 or similar means. As explained in Patent No. 2,619,982, this device at first gives a visual indication to the user that the heat input should be reduced and the timing of the cooking operation should be commenced. In the event that the visual indication remains unnoticed, the same device is adapted to emit an audible whistling sound. The device is further adapted to relieve the pressure within the vessel and maintain the correct pressure during the cooking operation.

At the end of the cooking time, the cooking operation is terminated by interrupting the heat supply, and the user then takes steps to reduce the pressure Within the vessel I. Experience has shown that the safest and easiest way for the average user to do this is to hold the cooker under water running from a faucet or to set it in a pan which is partly lled with water. The temperature within the vessel 2 is rapidly reduced thereby and consequently the pressure within the vessel decreases t approximately atmospheric pressure, at which time the member I4 is permitted to drop t0 its normal position. This indicates to the user that it is time to remove the lid or cover 2. Thus the novel venting device 6 provides a position indi-cation as to .whether or not substantial pressure exists in the cooker.

In the event of failure of the pressure regulating device to maintain a safe pressure within the cooker during operation, due to plugging of the valve or some other condition, the enlarged portion I9 of member It will be forced through the orifice I3. The force exerted by the pressure within the vessel causes the camming surface of the conical portion of section IS to deform the resilient inwardly-extending annular projection I2. When the holding strength of acvomss the projection I2 is exceeded by the upper force, which in this embodiment is arranged to be approximately 25 lbs. per sq. in, vessel pressure, the member I4 is moved upward until the flat upper surface 2l of the squared feet 2B engage the lower surface of the projection l2, The excess pressureholds the member in the'venting position shown in Fig. 4. This device thus serves as a safety means for preventing development of dangerous pressures within the cooker.

Y The air venting and indicating device disclosed in the Turner Patent No. 2,619,982 comprises only the upper cap portion l5, the cylindrical portieri I8 and an enlarged portion similar to that at i9. In that device the presence of an excess of pressure in the vessel causes the rigid i Amember to be forcibly ejected from its retaining member, resulting in frequent loss of the ejected member with consequent inconvenience to the user. It is also obvious that the device presents a source Aof hazard. In theimproved device of the present invention, the provision of the cylindrical portion 22 vand the squared feet portion '2D obviates these dillculties.

If for any reason, in this device or in the deviceof the Turner Patent No. 2,619,982, the movement of the rigid member Id i5 prevented, or if motion does occur but the excess pressure escape ports become clogged, the entire device is adapted to blow out of the opening in the pressure cooker lid. This pressure is usually set vabout lbs/sq. in. and thus acts as an additional safety measure to make for safe pressure cooker operation.

' Another embodiment of this invention is shown in Fig. 6; In this'embodiment, a movable member 23 is provided, having a cap or stop 24, a cylindrical portion 25 and an enlarged portion 2B,`which are essentially similar to the correspending portions of member I4 of the previous embodiment. At the bottom of member E3 is disposed a metal retaining ring 2l which is held in a hole 28 provided in cylindrical portion 2e.

A third embodiment is shown in Fig. 7. In thisv embodiment a movable member 30 includes a cap or stop 3 I, a cylindrical portion 32 and an enlarged portion 33, which are essentially similar to the previous embodiment. The retaining means on this device, however, consists of a disclike section 34 having a plurality of holes 35 provided therein (see Fig. 8). A cylindrical section 36 connects the enlarged portion 33 to the disclike section 34.

It is obvious that the metal retaining ring 2l of member 23 (Fig. 6) and the disc-like section 34 of member 30 (Fig. '7) operate in a manner similarto that of the squared foot section 2D of member it to permit free escape of excess pressure within the vessel without loss of the movable member.

Thus in each of the illustrated embodiments the movable member is provided with a retaining portion or stop to prevent ejection of said member.

It is evident that other embodiments or modifications of the device are possible, and it is to be understood that the invention is not limited to the embodiments disclosed.

l. In aV pressure cooker having an opening, an apertured resilient member disposed in said opening and secured to the pressure cooker, rigid sealing member extending through the aperture of -saidl resilient member and movable by pressure insaid cooker, a stop at the outer end oi said rigid member for preventing the same from becoming disengaged from said resilient member i 2. A structure according to claim l, wherein the portion of said rigid member between said rst stop and said sealing portion is of suiiioient length to permit substantial displacement of the rigid member during normal operation, so that said rigid member gives a clear indication of Whether pressure does or does not exist Within said cooker.

3. In a pressure cooker having a circular airvent opening dened by a single edge, a resilient member of general toroidal form having an annular groove to receive the edge dening said opening so as to support said member within the opening, said member also having an internal inwardly-extending annular projection, a rigid sealing member extending through said resilient member and movable by pressure in said cooker, a stop at the outer end of said rigid member engageable with said projection to prevent the rigid member from becoming disengaged from said resilient member when pressure does not exist in said cooker, a sealing portion on said rigid member intermediate the ends thereof engageable with said projection to seal the aperture of said resilient member in response to normal pressure but capable of passing through said aperture in response to abnormal pressure in the cooker, and a second stop at the inner end of said rigid member incapable of passing through said aperture and engageable with said projection, when said portion passes through said aperture, to prevent further displacement of said rigid member while permitting venting of pressure through said aperture.

4. In a pressure cooker having an air-vent and pressure-relief opening, an apertured resilient member retained in said opening and having an aperture-defining portion capable of resisting significant deformation by the normal cooking pressure existing in said cooker during operation but deformable by excessive pressures that may arise in the cooker, a rigid member freely supported by said resilient member and movable by pressures in said cooker, a sealing portion on said rigid member engageable with the inside of said aperture-denng portion and of a size and configuration to seat against said aperture-dening portion in response to the normal cooking pressure and to force itself through said apery ture by deforming said aperture-dening portion in response to excessive pressure,` and a stop on said rigid member spaced inwardly from said sealing portion and of a size and configuration to prohibit its passage through said aperture in response to excessive pressure but permitting venting of the pressure through said aperture.

5. A device according to claim 4, wherein said stop is generally of rectangular form.

6. A device according to claim 4, wherein said stop is in the form of a ring.

7. A device according to claim 4, wherein said stop is in the form of a disc having a plurality of holes therein.

8. In a pressure cooker having an air-vent and pressure-relief opening, an apertured resilient member retained in said opening and having an aperture-defining portion capable of resisting significant deformation by the normal cooking pressure existing in said cooker during operation but deformable by excessive pressures that may arise in the cooker, a rigid member freely supported by said resilient member and movable by pressures in said cooker, a sealing portion on said rigid member engageable with the inside of said aperture-deiining portion and of a size and configuration to seat against said aperture-deiinng portion in response to the normal cooking pressure and to force itself through said aperture by deforming said aperture-defining portion in response to excessive pressure, an indicating portion on said rigid member extending from said sealing portion within said aperture and projectable outwardly beyond said resilient member when said sealing portion seats against said aperture-dening portion, the projection oi said indicating portion serving to indicate the existence oi pressure in said cooker, and a stop on said rigid member spaced inwardly from said sealing portion and of a size and configuration to prohibit its passage through said aperture in response to excessive pressure but permitting venting of the pressure through said aperture.

9. In a device according to claim 8, said indicating portion including a stop further serving to prevent said rigid member from becoming disengaged from said resilient member when pressure does not exist in said cooker.

WILLIAM S. KENDRICK.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 360,781 Nye Apr. 5, 1887 701,607 Park June 3, 1902 1,313,554 Nielsen Aug. 19, 1919 2,160,398 Crowley May 30, 1939 2,276,502 McCoy Mar. 17, 1942 2,403,691 States July 9, 1946 2,429,149 Wittenberg Oct. 14, 194'? 

